Next chapter in my search for airframe corrosion

[Shadrach]

I have been actively seeking out corrosion on my bird for the last 5 years or so. I have found a little surface corrosion here and there, but nothing alarming. This year I pulled the wing root farings. While both side were corrosion free save for a bit of surface pitting on a few panels, the potential here could be great. The wings are taped to the fuselage with fabric backed aluminum tape. After many years of service the adhesive separates from the tape. Water can and will enter at the wing root and the fabric tape backing will hold a bit of moisture. I would urge anyone flying an older aircraft to have a look at this part of their aircraft. I cleaned, zinc'd and retreated the airframe with corrosion x. it took a full day, I have now cleaned and treated every nook and cranny of this airframe. I am confident that it will last as long as I want to fly it.

 

After tape removal. None of the existing tape was adhered to the airframe. All farings held in place with #4 and #6 sheetmetal screws plus 2 #10 machine screws amd nuts where the trailing edge of the flap meets the faring/fuselage.  I believe they were all #4s from the factory, but over the years we've had to go up a size in some areas.

 

 

Tape came out in a single strip. Fabric had delaminated from the aluminum. It was powdery and no longer serving any purpose other than to hold water... 

 

Cleaned with adhesive remover, then all nooks, crannies and crevices sprayed with Corrosion X.

 

Most of the yellow seen in this pic is Zinc Chromate that was applied from the inside 5 years ago when I had the interior out. I was aggressive with it before we sound proofed and it made it's way out of the wing root. 

 

All body panels cleaned and had their backsides treated with zinc phosphate paint. 

 

Cleaned thoroughly with denatured alcohol, zinc phosphate touch up and re-taped with fresh aluminum tape. The second photo also showcases that the aircraft came with a true slotted flap.

 

 

 

Edited October 19, 2015 by Shadrach

[Glenn]

This is a very useful post.  Thanks.

[carusoam]

Ross,

Really nice photo documentation!   A couple of questions come to mind...

What holds the faring pieces in place, just screws? Or screws and a couple rivets?

Did you apply a more modern tape? (To seal air leaks out of the cabin(?))

Best regards,

-a-

[Mooneymite]

Helpful post.

Thanks!

[Shadrach]

 

Ross,

Really nice photo documentation!   A couple of questions come to mind...

What holds the faring pieces in place, just screws? Or screws and a couple rivets?

Did you apply a more modern tape? (To seal air leaks out of the cabin(?))

Best regards,

-a-

 

No Rivets needed to be drilled to remove the farings.  The rear section of faring is two pieces riveted together, but is held in place with #4 screws and 2 #10 machine screws with nuts on the back; it comes off in one piece.  It is flexed when in place, so one should expect it to "pop" off. One should also be prepared to flex it into proper position when reinstalling.  I find Mooney's sheet metal work to be impressive to say the least.  They were not afraid to implement smooth compound curves.  

I've updated the original post on a lap top with explanations for the pics.  I took the photos with an iPad and therefore uploaded from that device. I gave up on trying to edit with that device; the auto correct also makes things interesting... It's a major pain to edit and organize photos on anything but a computer. 

Edited October 17, 2015 by Shadrach

[jetdriven]

A real light bead of PRC will also seal those panels from water.  I'm gonna pull mine and have a look as well. 

Edited October 16, 2015 by jetdriven

[Bob_Belville]

Ross, the Persian rug in the hanger is a nice touch. 

https://www.pinterest.com/pin/540432024010254140/

[Shadrach]

Ross, the Persian rug in the hanger is a nice touch. 

https://www.pinterest.com/pin/540432024010254140/

Thanks!

Yes, our steed lives in a carpet lined hangar.  All of those Persians rugs are real, but they are all damaged beyond being fit for the house. I think they make for a pleasant place to work, but my mechanic hates using a creeper on them. The mooney is so low to the ground, that I typically eschew the creeper in favor of crawling, which is why I prefer carpet.

[MyNameIsNobody]

Persian rugs in the hanger?  Wholly awesomeness Batman!  She (your bird) is spoiled.

 

Lucky girl...

[M20F-1968]

I would be careful about rugs in the hanger at least under the plane.  They will hold moisture and be a possible predisposing factor relative to corrosion.

John Breda

[DXB]

Wish my hangar was dry enough to throw a Persian rug under my plane!  I certainly spend more time there than at my living room coffee table.  Unfortunately the asphalt floor with poor drainage lead to giant puddles after a heavy rain    Wonder if I'd be better off parking outdoors or in a swamp somewhere.

[Shadrach]

I would be careful about rugs in the hanger at least under the plane.  They will hold moisture and be a possible predisposing factor relative to corrosion.

John Breda

While I don't have the nicest hangar on the block, it is certainly weather tight. If water breaches the hangar back to where the rugs are, the dampness won't matter because the plane will be covered in timbers and galvanized corrugate... Most of the Ts at our drome are gravel floored with a small asphalt parking pad. I'm happy to have moved up to poured concrete and Persian rugs.

Edited October 23, 2015 by Shadrach

[HRM]

Speaking of corrosion searches...

When Bruce Jaeger came to KBPT to install my Spatial Interior we discussed corrosion.

It turns out he is not only a fanatic about it, but quite the expert on it, particularly with Mooneys.

While we were doing the interior, he grilled me on corrosion ADs and did some checking on his own.

Then he smugly stated that one of the most often overlooked areas was in the gear bays near the mouse boots! I told him I didn't even know what a 'mouse boot' looked like and he promptly dragged me down under a wing to show me. Then he proceeded to 'get up under' the gear bay and after looking at both sides he almost dejectedly declared that my bird was clean. All hunters get dejected when they fail to bag game.

It turns out that water can lay up under there, seep under the main spar and then, well, you know.

So, check up under there--fairly easy to do. 

[Shadrach]

Speaking of corrosion searches...

When Bruce Jaeger came to KBPT to install my Spatial Interior we discussed corrosion.

It turns out he is not only a fanatic about it, but quite the expert on it, particularly with Mooneys.

While we were doing the interior, he grilled me on corrosion ADs and did some checking on his own.

Then he smugly stated that one of the most often overlooked areas was in the gear bays near the mouse boots! I told him I didn't even know what a 'mouse boot' looked like and he promptly dragged me down under a wing to show me. Then he proceeded to 'get up under' the gear bay and after looking at both sides he almost dejectedly declared that my bird was clean. All hunters get dejected when they fail to bag game.

It turns out that water can lay up under there, seep under the main spar and then, well, you know.

So, check up under there--fairly easy to do. 

I believe the "mouse boot" you refer to is the area where the actuating rods enter the gear well. I check that area every year when I do the "preload check". Most of the lower lap areas on my bird are sealed by previous fuel leak residue...

Edited October 27, 2015 by Shadrach

[Marauder]

I believe the "mouse boot" you refer to is the area where the actuating rods enter the gear well. I check that area every year when I do the "preload check". Most of the lower lap areas on my bird are sealed by previous fuel leak residue...

You guys have the cloth boot on that area?

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[Shadrach]

 

You guys have the cloth boot on that area?

 

 

Sent from my iPad using Tapatalk

Yup! I'm guessing it's synthetic or it would have rotted out decades ago.

[HRM]

I believe the "mouse boot" you refer to is the area where the actuating rods enter the gear well. I check that area every year when I do the "preload check". Most of the lower lap areas on my bird are sealed by previous fuel leak residue...

Yes. the boots are just small rubber covers that the rods go through. The problem is that there is a flat area up under there where water can collect and lay. It then seeps under the spar and can cause hellacious corrosion issues.